CVE-2018-17636 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.2.0.9297. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the handling of the id property of a aliasNode. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-6472.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17636 represents a critical remote code execution vulnerability affecting Foxit Reader version 9.2.0.9297, classified under CWE-476 as NULL Pointer Dereference. This vulnerability stems from insufficient input validation within the PDF parsing engine when processing the id property of aliasNode elements. The flaw occurs when the application attempts to perform operations on an object without first verifying its existence, creating a dangerous condition where a null pointer dereference can lead to arbitrary code execution. Attackers can exploit this by crafting malicious PDF documents containing specially formatted aliasNode elements with invalid id properties, which when processed by the vulnerable Foxit Reader application trigger the exploitable condition. The vulnerability requires user interaction to be effective, meaning victims must either visit a malicious webpage hosting the crafted PDF or directly open the malicious file, making it particularly dangerous in phishing campaigns and targeted attacks. This issue falls under the ATT&CK technique T1203 - Exploitation for Client Execution, where adversaries leverage application vulnerabilities to execute code on victim systems. The impact extends beyond simple code execution as the vulnerability operates within the context of the current process, potentially allowing attackers to escalate privileges or access sensitive system resources. The vulnerability's exploitation mechanism aligns with common web application security flaws where improper object validation leads to memory corruption issues. This particular flaw demonstrates how PDF processing applications remain vulnerable to memory safety issues despite years of security improvements in document handling software. The ZDI-CAN-6472 reference indicates this vulnerability was recognized by the Zero Day Initiative, highlighting its significance in the cybersecurity community. Organizations using Foxit Reader should immediately implement patch management procedures to address this vulnerability, as the attack surface includes web browsers, email clients, and any system where PDF documents are opened automatically. The vulnerability's classification as a remote code execution flaw makes it particularly attractive to threat actors seeking persistent access to compromised systems. Security teams should monitor for exploitation attempts targeting this specific vulnerability, as it represents a well-documented attack vector that has been actively exploited in the wild. The remediation process involves updating to Foxit Reader version 9.2.1 or later, which includes proper validation of object existence before operations are performed. Network segmentation and application whitelisting can provide additional layers of defense while patches are deployed, as these measures help prevent unauthorized PDF processing on critical systems.